A man fasts during Ramadhan and his thirst becomes severe, so he drinks. So, what is the ruling?

Answer:

He must make up for the day of fasting and there is no expiation due to him according to the most correct opinion between the two views of the scholars. If he was lax regarding that, he must make repentance to Allaah along with making up for the day of fasting.

In reference to expiation, it is not obligatory upon anyone other that the person who has sex during the day in Ramadhan who is obliged to fast. This is because the Hadith has been reported concerning that according to the correct view.